<div class="problem-statement">
 <div class="header">
  <div class="title">
   F. Parametric MST
  </div>
  <div class="time-limit">
   <div class="property-title">
    time limit per test
   </div>1 second
  </div>
  <div class="memory-limit">
   <div class="property-title">
    memory limit per test
   </div>256 megabytes
  </div>
  <div class="input-file">
   <div class="property-title">
    input
   </div>standard input
  </div>
  <div class="output-file">
   <div class="property-title">
    output
   </div>standard output
  </div>
 </div>
 <div>
  <p>You are given $n$ integers $a_1, a_2, \ldots, a_n$. For any real number $t$, consider the complete weighted graph on $n$ vertices $K_n(t)$ with weight of the edge between vertices $i$ and $j$ equal to $w_{ij}(t) = a_i \cdot a_j + t \cdot (a_i + a_j)$. </p>
  <p>Let $f(t)$ be the cost of the <a href="https://en.wikipedia.org/wiki/Minimum_spanning_tree">minimum spanning tree</a> of $K_n(t)$. Determine whether $f(t)$ is bounded above and, if so, output the maximum value it attains.</p>
 </div>
 <div class="input-specification">
  <div class="section-title">
   Input
  </div>
  <p>The input consists of multiple test cases. The first line contains a single integer $T$ ($1 \leq T \leq 10^4$) — the number of test cases. Description of the test cases follows.</p>
  <p>The first line of each test case contains an integer $n$ ($2 \leq n \leq 2 \cdot 10^5$) — the number of vertices of the graph.</p>
  <p>The second line of each test case contains $n$ integers $a_1, a_2, \ldots, a_n$ ($-10^6 \leq a_i \leq 10^6$).</p>
  <p>The sum of $n$ for all test cases is at most $2 \cdot 10^5$.</p>
 </div>
 <div class="output-specification">
  <div class="section-title">
   Output
  </div>
  <p>For each test case, print a single line with the maximum value of $f(t)$ (it can be shown that it is an integer), or <span class="tex-font-style-tt">INF</span> if $f(t)$ is not bounded above. </p>
 </div>
 <div class="sample-tests">
  <div class="section-title">
   Example
  </div>
  <div class="sample-test">
   <div class="input">
    <div class="title">
     Input
    </div>
    <pre>5
2
1 0
2
-1 1
3
1 -1 -2
3
3 -1 -2
4
1 2 3 -4
</pre>
   </div>
   <div class="output">
    <div class="title">
     Output
    </div>
    <pre>INF
-1
INF
-6
-18
</pre>
   </div>
  </div>
 </div>
</div>